2004 Dodge Ram

Engine Light on, Diagnostics said ambient temp, replaced sensor checked wiring

OK; In cab temp reads -40 so there must be a open circut, reset no go, HELP

I’m not sure what you mean by “reset.” When this happened to me I disconnected my negative battery terminal cable for several minutes, then re-connected. This “wiped” the computer and rebooted it. Upon re-connection my light went out go out.